Process for the manufacture of artificial lithographic stones.



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TED STATES PATENT OFFICE.

PROCESS FOR THE MANUFACTURE OF ARTIFICIAL LITHOGRAIHIC STONES.

No Drawing.

To all whom it may concern:

Be it known that I, VICTOR HENRI JOSEPH Humane, a subject of the King of Belgium, residing at 82 Rue Sans-Souci, Ixelles- Brussels, in the Kingdom of Belgium, have invented certain new and useful Improvements in Processes for the Manufacture of Artificial Lithographic Stones, of which the following is a specification.

This invention relates to the manufacture of artificial lithographic stones.

It has for object a process which will allow of obtaining compact stones with homogeneous and very fine grain, which are not porous, and which will not crack from exposure to the air and are particularly resistant to atmospheric influences.

To this end the invention consists essentiallyin impregnating with water the mixture of materials entering into the compositions of the artificial lithographic stone, while it is being subjected to a high degree of pressure so as to effect, by the increase of volume of the molecules of the materials I under the action of the water, the complete expulsion of the air contained in the mass.

The mixture used for the manufacture is composed essentially of cement, white stone (pierre dEum'Zle) trass, and white sand, and this mixture, treated according to the process forming the subject of the invention is kept for a long time in water in order to obtain a particularly slow setting contributing to the obtaining of a particularly homogeneous and resistant product. The drying is afterward efl'ected also in a slow and uniform manner in order to preserve all the qualities of the stone.

In carrying out the invention I prefer ably proceed in thehfollfowing malnner. mix 3 parts by weig t o cement, part 0 finely ground white stone, part of trass and 1 par 0 w ute san This mixture is afterward suitably screened and bolted so as to eliminate lumps or impurities. The

mixture is afterward placed in molds the not affected by the atmosphere.

sides of yhich are "raviaeaf wlra sma Specification of Letters Patent.

Patented Feb. 22, 1916.

Application filed May 27, 1913. Serial No. 770,225.

jagged to a degree of high fpressure 130 to tons )er s uar meter or exam e e- "veloped by means of a hydraulid press. ater is afterward admitted into the vessel 0 a suitable depth as for example about 1.5 m. and the high pressure to which the mixture is subjected is maintained. Under these conditions the water which penetrates into the mold through the small holes made in the sides gradually impregnates the mixture and causes the molecules of cement to swell. As the mass cannot increase in volume by reason of the pressure to which it is subjected the air contained in the mass is completely driven out of the mold. The pressure is maintained until it is found that the bubbles of air no longer rise to the surface of the water contained in the vessel. This result is generally attained after a period of about 24 hours under pressure in the water. The air being then completely expelled from the mass, the latter commences to set and is free from pores. The water is then allowed to flow out of the vessel and the stone is withdrawn from the mold after having been further maintained under pressure during a certain time (3 hours for example). After being submitted to the action of the air for a short time (48 hours at the most) it is placed in water and is allowed to remain therein for a long time, for example, for about 1 to 3 months so as to retard the hardening of the stone and to insure that this hardening shall take place at first in the central part of the mass and gradually extends toward the outer surface. After this prolonged stay in the water the stone is left to. dry slowly in a damp place and at a regular temperature where it is protected from the action of currents of air. After being left from 2 to 4 months to dry the stone can be pumiced and used in the same manner as a natural stone. The stone thus obtained is free from pores, unctuous to the touch, does not absorb moisture and is This result is principally due to the wetting under ffi'lifeds. The mold being thus filled with dry material representing for example a thickness of. 12 centimeters, the mixture 1s compressed in the dry state so as to reduce the thickness of the material contained in the mold to about 10 centimeters. The mold 5 is then placed in a vessel serving-to contain water, and the contents of the mold are suba clear tint and is particularly smooth and soft to the touch. These properties are obtained in a particularly favorable manner when cements of different manufacture or origin possessing for example, different qualities, are usedin the composition of the mixtures; in this case in fact the advantageous properties of one quality of cement tend to compensate for the defects of the other qualities employed conjointly in the mixture and vice versa, and a final mixture is obtained, the properties of which are particularly uniform and regular. The addition of white stone to the mixture of the cements (for example of 3 parts of cements of different origins) increases the resistance of the stone formed, while the trass regulates and augments the cohesion and the white sand renders the final product less sensitive to outer influences while increasing the whiteness of the stone.

What I claim is:

1. A process for the manufacture of artificial lithographic stone, said process consisting in mixing cement, trass, white stone and sand, then compressing the mixture in the dry state in a suitable mold, then impregnating the mixture with water while subjecting it to a high pressure and finally drying slowly the compressed mixture.

2. A process for the manufacture of artificial lithographic stone, said process consisting in mixing cement, trass, white stone and sand, then compressing the mixture in the dry state in a suitable mold, then impregnating the mixture with water when it is in a compressed state, then allowing the stone thus obtained to remain in water for a very long time, and finally drying the stone slowly.

3. A process for the manufacture of artificial lithographic stone, said process consisting in mixing cement, trass, white stone and sand, then compressing the mixture in the dry state in a suitable mold, then impregnating said mixture with water while subjecting it to the action of a high pres- Gopies of this patent may be obtained for five cents each, by addressing the Commissioner 01' Iatents,

ficial lithographic stone, said process con-.

sisting in mixing cement, finely ground White stone, trass and white sand, then screening and bolting said mixture, placing said mixture in a suitably perforated mold, ramming the mixture as the filling of the mold proceeds, then compressing the mixture in the dry state then placing the mold with the mixture contained therein in a vessel adapted to contain water, afterward subjecting the mixture to the action of water while it is compressed under a high pressure, whereby the air contained in the mass is completely expelled, then withdrawing the stone thus obtained from the mold, then maintaining the stone in water for a period of about 2 to 4 months and finally drying the stone in a damp place while being protected from currents of air,

said drying operation being efi'ected during about four months.

5. The process for the manufacture of artificial lithographic stone, said process I consisting in forming said stone with a mixture of three parts of cement, one part of finely ground white stone, one part of trass and one part of white sand, then suitably compressing and impregnating said mixture and finally drying slowly the stone formed by the compression of the mixture.

In testimony whereof I have afiixed my signature in presence of two witnesses.

VICTOR HENRI JOSEPH HERENG. Witnesses:

JACQUE BEDE, G. DEMARET.

Washington, D. 0. 

